APPLICANT'S ABSTRACT: Alcoholism is a leading cause of morbidity and mortality among rural Native Americans. Research suggests there is a link between susceptibility for problems associated with alcohol abuse and low brain serotonin levels. A potential contributor to low brain serotonin levels is low dietary intake of the essential amino acid tryptophan, serotonin's natural precursor. Dietary studies report Native American diets are high in carbohydrates and fats and low in quality proteins. Low intake of the micronutrients that convert tryptophan to serotonin are also reported. We hypothesize that Native American populations may be at risk for alcohol-related problems due to inadequate intake of tryptophan or the micronutrients that convert it to serotonin. This pilot study will involve a random sample of 30 adult Native American males and 30 adult Native American females living in Caddo County, Oklahoma. 24-hour dietary recalls will be analyzed to quantitate total protein and micronutrient levels and give qualitative data on tryptophan consumption. The Food Frequency Questionnaire will provide data on long-term dietary practices. The Health Habits and History Questionnaire will provide additional information on dietary behaviors. Blood tryptophan levels will be analyzed using high performance liquid chromatography to assess whether blood tryptophan levels are low relative to national norms. AUDIT will provide information on drinking behavior. DrInC, with special focus on conditions associated with low brain serotonin levels, will provide information on severity of negative consequences. Analysis will be conducted by constructing confidence intervals for nutritional data in the sample and comparing this to national norms. Additionally, case-control comparisons will examine the association between nutritional variables and problem drinking. We predict that low tryptophan intake or deficiency in at least one micronutrient will be found in this Native American population. We further predict that severity of drinking and negative consequences will be greater among those with lower values of tryptophan or the micronutrients necessary for the production of serotonin.